Mobile QR Code QR CODE : The Korean Institute of Power Electronics
Title Voltage Control Scheme in Synchronous Reference Frame for Improving Dynamic Characteristics in Parallel Operation of Double-Conversion UPSs
Authors Jae-Sing Mo ; Young-Doo Yoon ; Hyo-Jun Ryu ; Min-Sung Lee ; Seung-Cheul Choi ; Sung-Min Kim ; Seok-Min Kim ; Ho-Hyun Kang ; Hee-Jung Kim
Page pp.283-290
ISSN 1229-2214
Keywords Additional feed-forward; Discrete-time current control; Double-conversion UPS; Synchronous reference frame controller; 2-DOF control
Abstract This study proposes a voltage control scheme in a synchronous reference frame to improve the dynamic characteristics of double-conversion UPSs. UPSs need to control positive and negative sequence voltage, so that positive and negative sequence extractors are generally used to obtain each sequence of the voltage and current. Voltage and current controllers for each sequence are implemented. However, the extractor causes considerable delay, and the delay restricts the control performance, especially for the current controller. To improve the dynamics of the current controller, the proposed scheme adopts a unified current controller without separating positive and negative sequences. By using discrete-time current controller, the control bandwidth can be extended significantly so that negative sequence current can be controlled. To enhance the performance, an additional feed-forward technique for output voltage regulation is proposed. The validity of the proposed controller is verified by experiments.